Constrained exceptional supersymmetric standard model with a Higgs signal near 125 GeV

We study the parameter space of the constrained exceptional supersymmetric standard model (${\mathrm{cE}}_6\mathrm{SSM}$) consistent with a Higgs signal near 125 GeV and the LHC searches for squarks, gluinos and $Z^{\prime }$. The ${\mathrm{cE}}_6\mathrm{SSM}$ parameter space, consistent with correct electroweak symmetry breaking, is represented by scans in the $(m_0,M_{1/2})$ plane for fixed $Z^{\prime }$ mass and $\tan \beta$, with squark, gluino and Higgs masses plotted as contours in this plane. We find that a 125 GeV Higgs mass only arises for a sufficiently large $Z^{\prime }$ mass, mostly above current limits, and for particular regions of squark and gluino masses corresponding to multi-TeV squark masses, but with lighter gluinos typically within reach of the LHC 8 TeV or forthcoming 14 TeV runs. Successful dark matter relic abundance may be achieved over all the parameter space, assuming a binolike lightest supersymmetric particle with a nearby heavier inert Higgsino doublet and decoupled inert singlinos, resulting in conventional gluino decay signatures. A set of typical benchmark points with a Higgs near 125 GeV is provided which exemplifies these features.

Figure 1

Allowed region for ${\mathrm{cE}}_6\mathrm{SSM}$ with $\tan \beta =10$, $s=5$,10, 20, 50, 100 TeV in cyan (light grey), blue (medium-dark grey), red (dark grey), purple (medium-light grey) and green (medium grey) respectively with ${\lambda }_{12}=0.1$, while contours are produced with a universal $\kappa$ coupling and ${\lambda }_3$ are varied, with ${\lambda }_3$ (and hence ${\mu }_{\mathrm{eff}}$) $\le 0$.

Figure 2

Squark and gluino mass contours (left panel) and Higgs mass contours (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with $\tan \beta =10$, ${\lambda }_{12}=0.1$, $s=5\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=1.889\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ respectively so that ${\mu }_{\mathrm{eff}}\le 0$.

Figure 3

Squark and gluino mass contours (left panel) and Higgs mass contours (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with $\tan \beta =10$, ${\lambda }_{12}=0.1$, $s=10\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=3.778\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ so that ${\mu }_{\mathrm{eff}}\le 0$.

Figure 4

Squark and gluino mass contours (left panel) and Higgs mass contours (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with $\tan \beta =10$, ${\lambda }_{12}=0.1$, $s=20\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=7.564\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ so that ${\mu }_{\mathrm{eff}}\le 0$.

Figure 5

Squark and gluino mass contours (left panel) and Higgs mass contours (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with $\tan \beta =10$, ${\lambda }_{12}=0.1$, $s=50\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=18.996\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ so that ${\mu }_{\mathrm{eff}}\le 0$.

Figure 6

Squark and gluino mass contours (left panel) and Higgs mass contours (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with $\tan \beta =10$, ${\lambda }_{12}=0.1$, $s=100\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=37.808\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ so that ${\mu }_{\mathrm{eff}}\le 0$.

Figure 7

Higgs mass contours for $\tan \beta =3$ (left panel) and $\tan \beta =30$ (right panel) in the $(m_0,M_{1/2})$ plane of the cE6SSM with ${\lambda }_{12}=0.1$, $s=10\mathrm{TeV}$, corresponding to $M_{Z^{\prime }}=3.779\mathrm{TeV}$. Scans are produced with a universal $\kappa$ coupling varied over $\{0,3\}$ and ${\lambda }_3$ over $\{-3,0\}$ so that ${\mu }_{\mathrm{eff}}\le 0$.